In recent years, electric vehicles using electric motors as driving sources as well as so-called hybrid cars having multiple kinds of driving sources such as electric motors and gasoline engines have been put to practical use. These electric vehicles and the like are equipped with power storage devices such as batteries or capacitors as power sources for supplying electricity as energy to the electric motors or the like. For example, secondary batteries that can be repeatedly charged and discharged, such as nickel-cadmium batteries (Ni—Cd batteries), nickel-hydride batteries or lithium-ion batteries, are used as batteries.
In a case where secondary batteries are used as a power source, they are mounted on a vehicle in such a manner that they are made up of battery modules having battery cells stacked and these battery modules are housed within a power source case. The power source case, the battery modules housed within the power source case and other internal components are collectively referred to as a power source pack.
Conventionally, a battery pack has been mounted in a luggage space (trunk). Due to a request to keep sufficient volume of the luggage space, however, a configuration in which the battery pack is arranged in a cabin may be employed depending on the types of vehicles. In a case where a power source pack is arranged on a floor panel, there are concerns that the temperature of the power source pack increases because of the heat from a lower surface of the floor panel and this has an adverse effect on the performance of the power source pack. It is assumed that, in summer, the radiant heat reflected from a road is conducted through the floor panel to the power source pack. It is also assumed that, in a vehicle where an engine is mounted, the heat from an exhaust path running on the lower surface of the floor panel is conducted through the floor panel to the power source pack as a result of the increased temperature of the exhaust path.
If a passenger spills water on a surface of the floor panel, the water may flow into the power source pack and remain there depending on a position where the power source pack is arranged.
Referring to FIG. 2 of Japanese Patent Laying-Open No. 2004-237790, a power source pack is mounted under a passenger seat. In this structure for mounting the power source pack, however, the radiant heat reflected from a road may be conducted through a floor panel to the power source pack. Furthermore, if water is spilled on a surface of the floor panel, the water may flow into the power source pack and remain there.